1. Field of the Invention
This invention relates to mine roof truss assemblies and a method of establishing the same and, more specifically, it relates to an improved assembly which employs a combination of an anchored elongated support member with a flexible underlying tension member.
2. Description of the Prior Art
In connection with underground mining operations it has been known to provide various means of roof support so as to resist potentially hazardous mine cave-ins. Among the known systems are those which use truss members which are anchored to the mine roof in the passageway areas so as to provide mechanical support for the overlying roof strata.
It has previously been known to support a mine roof by securing timbers or steel crossbeams to the roof by means of expansion bolts which are oriented generally upwardly and outwardly with respect to the centerline of the line passageway. See U.S. Pat. No. 2,667,037.
It has also been known to employ angularly upwardly and outwardly oriented mine roof holes wherein a flexible cable member has its ends anchored as a result of being wrapped around a wedge member which has been forced into the hole. See U.S. Pat. No. 3,601,994. In this patent, one embodiment has longitudinally oriented timbers disposed between the cable and the mine roof.
It has also been known to provide angularly upwardly and outwardly anchored roof bolts to which are secured cable members which are tensioned by means of a turnbuckle. See U.S. Pat. No. 3,427,811.
While these prior art systems have offered certain advantages, there remains a need for an efficient roof truss system which is economical to employ, may be rapidly installed and provides effective safe conditions in a potentially hazardous area.